Problem.Dimension = 2;
Problem.LowerBound = [-4,-4];
Problem.UpperBound = [4,4];
Problem.ObjFunc = @(x)(-20.*exp(-0.2.*sqrt((x(:,1).^2+x(:,2).^2)./2)))-exp((cos(2.*pi.*x(:,1))+cos(2.*pi.*x(:,2)))./2);

Algorithm.PopulationSize = 20;
Algorithm.F = 0.5;
Algorithm.CR = 0.5;
Algorithm.StopCriteria = [1,15000];

[fval, sol, EvaluationNum, GenerationNum] = differential_evolution(Problem,Algorithm)